The present invention relates generally to communications systems and more specifically to countermeasures used for differentiation of live nuclear warheads from dummy warheads released by intercontinental ballistic missiles. Existing anti-ballistic missile (ABM) systems can be easily nullified with inexpensive penetration aids. One common way of achieving these ends is to saturate the ABM tracking system with multiple warheads and decoys causing the defensive country to fire their antimissile missiles at both, being unable to distinguish one from another. Once the defensive country has fired all of their antimissile missiles they are helpless to any further attack. Since the relative cost of deploying decoys is much less than the missiles for destroying them, some method is needed to differentiate between decoys and nuclear warheads.
The only viable method presently available to distinguish warheads from decoys consisting of observing the behavior of the decoys and warheads as they reenter the atmosphere. Normally lighter decoys, such as fragments of the last stage of the ICBM, foil-covered balloons, etc., will fall at a much slower rate than a nuclear warhead once they reenter the atmosphere. By tracking these objects with radar, their reentry speed and trajectory can be easily determined thereby allowing the radar operator to pick out the read warheads from the decoys. This method fails however if the decoys are made of the same weight and shape to have the same trajectory and falling rate as the nuclear warheads. The primary disadvantage with this system however is that the trajectory of most ICBM's is such that their reentry point into the atmosphere is at a point which is normally close to its intended target. This, of course, leaves little time for analysis, identification, and retaliation thereby lessening the chances for a successful defense.